Related Art
The present invention relates to the process for the preparation of (hydroxyphenoxy)-carboxylates. These compounds are suitable intermediates for the synthesis of biological and in particular herbicidally active ingredients such as Fusilade and Dowco 453.
Various methods of preparing (hydroxyphenoxy)-carboxylates are known in the art. For instance, U.S. Pat. No. 4,489,207 discloses a process for the production of 2-(hydroxyphenoxy)-carboxylates. In the processes discussed therein as prior art there is described a reaction of hydroquinone with 2-halo carboxylate in an alcoholic solution in the presence of sodium alcoholate. Also disclosed is the reaction of hydroquinone with ethyl chloroacetates in the presence of boron trifluoride. In addition there is disclosed the alkylation of hydroquinone in the form of its disodium salt with 2-bromocarboxylates in certain water-soluble organic solvents.
The process of the invention disclosed in U.S. Pat. No. 4,489,207 is the reaction of a dihydroxybenzene compound with a 2-halo-fatty acid ester in the presence of calcium hydroxide in dimethyl sulfoxide (DMSO) at from 0.degree. C.-100.degree. C.